[Quitti]

Death magic skill lessens the chance of getting old age afflictions (Good for eg. Shinuyama & LA Agartha). F1N1 item Elixir of Life and B2 Boots of Youth also prevent the unit from gaining any old age afflictions. I have no idea about the chance to get those afflictions based on how much old age they have though, but as the old age malus get worse with age, I suppose so does the chance to gain afflictions rise. And like stated, it's not just disease that can happen, I suppose everything the unit is capable of getting can afflict the commander in the late winter. I've seen at least mages going blind, feebleminded, losing arm and so on, but disease itself seems the most common.